2-巯基-4-甲基嘧啶盐酸盐的合成

Synthesis of 2-Mercapto-4-methylpyrimidine Hydrochloride

以甲酸甲酯与丙酮缩合生成丁酮烯醇钠,再与甲醇缩醛化反应得4,4-二甲氧基-2-丁酮,进一步和硫脲环合反应制得2-巯基-4-甲基嘧啶盐酸盐。考察了缩合反应的物料配比、反应时间及反应温度,缩醛化试剂,环合反应的原料配比、温度及环合时间。得出缩合反应最佳配比甲醇钠∶丙酮∶甲酸甲酯(摩尔比)为1∶1.1∶3,40℃下反应4h,收率达78.7%;采用100%浓硫酸作缩醛化试剂,可以避免水分对反应的影响;环合反应最佳配比4,4-二甲氧基-2-丁酮∶硫脲∶盐酸(摩尔比)为1∶1.05∶2,60℃下反应2h,收率为95.1%。通过红外光谱(FT-IR)和质谱(MS)对产品进行了结构表征。

2-Mercapto-4-methylpyrimidine hydrochloride was synthesized by condensation reaction which was taken place through dropping the mixture of acetone and methyl formate into methanol solution of sodium methoxide, acetal reaction which was carried out between sodium formyl acetone and methanol to form 4,4-dimethoxy-2-butanone in the presence of sulfuric acid, and cyclized using 4,4-dimethoxy-2-butanone, thiourea and hydrochloride acid in the methanol solution. All the factors influencing to each reaction have been discussed. It was found that the high yield of condensation reaction was obtained at 40 ℃ for 4 h and the molar ratio of sodium methoxide：acetone：methyl formate is 1：1. 1：3. The reagent of acetal reaction was 100% sulfuric acid. And the high yield of cyclized reaction was obtained at 60 ℃ for 2 h and the molar ratio of 4,4-dimethoxy-2-butanone ：thiourea- hydrochloride acid is 1 ： 1.05 ： 2. The products were characterized by FT-IR and MS.